AU2018329881A1

AU2018329881A1 - Antitumor agent and antitumor effect potentiator

Info

Publication number: AU2018329881A1
Application number: AU2018329881A
Authority: AU
Inventors: Tomonori Haruma
Original assignee: Taiho Pharmaceutical Co Ltd
Current assignee: Taiho Pharmaceutical Co Ltd
Priority date: 2017-09-08
Filing date: 2018-09-06
Publication date: 2020-03-26
Anticipated expiration: 2038-09-06
Also published as: KR102584306B1; JPWO2019049956A1; EP3682882A4; RU2020109716A3; US20210030738A1; RU2020109716A; KR20200037354A; JP7074760B2; TW201919627A; MA50251A; EP3682882A1; WO2019049956A1; AU2018329881B2

Abstract

The purpose of the present invention is to provide a novel antitumor agent that exhibits a remarkably excellent antitumor effect and has few side effects. The present invention relates to an antitumor agent characterized by the concomitant administration of an acyl thiourea compound represented by general formula (I) or a salt thereof and an immune checkpoint regulator.

Description

DESCRIPTION

TITLE OF INVENTION: ANTITUMOR AGENT AND ANTITUMOR EFFECT POTENTIATOR

TECHNICAL FIELD [0001]

The present invention relates to an antitumor agent, an antitumor effect potentiator, and a kit preparation combining an acyl thiourea compound or a salt thereof with an immune checkpoint molecule regulator.

BACKGROUND ART [0002]

4-[2-Fluoro-4-[[[(2-phenylacetyl)amino]thioxomethyl]amino]-phenoxy] -7-methoxy-N-methyl-6-quinolinecarboxamide is an antitumor agent having reduced side effects (PTL 1), and has been known to show desirable antitumor-effect potentiating effect when used with other antitumor agents (PTL 2). A recent study reports that such an acyl thiourea compound inhibits osteoclast differentiation by way of CSF1R inhibition, and shows antitumor effects in an osteolytic bone metastasis tumor model (NPL 1). Inhibitory effect against enzymes of the TAM family has also been shown (NPL 2).

[0003]

In addition to being involved in osteoclast differentiation, CSF1R is also a factor that modulates proliferation of macrophages occurring as precursor cells of osteoclasts, and proliferation of tumor-associated macrophages involved in tumor malignancy, and the effects of its inhibitor on immunity have been reported (NPL 3, 4). Protein tyrosine kinase 3 (TYRO3), AXL (AXL receptor tyrosine kinase), and MERTK (MER proto-oncogene, tyrosine kinase) of the TAM Family are also known to have important roles in intratumoral microenvironment factors such as tumor-associated macrophages, bone marrow-derived immunosuppressor cells, intratumoral vascular endothelial cells, and tumor-associated fibroblasts (NPL 5, 6).

[0004]

Cancer immunotherapy has been developed as a new form of cancer therapy. Activation of adaptive immune reaction is initiated by binding of an antigenic peptide-MHC complex and T-cell receptor (TCR). The binding is regulated by costimulation or coinhibition due to binding of the B7 family - a costimulatory molecule - and its receptor

CD28 family. Specifically, T cells require two characteristic signaling events for antigenspecific activation, and T cells stimulated solely by antigen without costimulation with the B7 family assume a state of unresponsiveness (anergy), inducing immune tolerance.

[0005]

By taking advantage of this mechanism, cancer cells escape from immunological surveillance and continue their growth by inhibiting activation of antigen-specific T cells. For cancer treatment, it is therefore considered effective to enhance costimulation or block coinhibition to induce an anti-tumor immune response in the body of a cancer patient and thereby control a tumor escaping from immunity. To this end, various types of immunotherapies that target costimulatory molecules (stimulatory costimulatory molecules) or coinhibitory molecules (suppressive costimulatory molecules) have been proposed (NPL 7). For example, nivolumab (human IgG4 monoclonal antibody against human PD-1) has been used for the treatment of cancers such as malignant melanoma as an immune checkpoint molecule regulator that activates T cells by inhibiting binding of PD-1 and its ligands (PD-L1 and PD-L2) (NPL 1, NPL 8). Involvement of a tumor-associated macrophage as a resistance mechanism against such cancer immunotherapy has also been indicated (NPL 9, 10).

[0006]

An acyl thiourea compound represented by the general formula (I) below or a salt thereof is known as a c-Met inhibitor (PTL 1, 3), and there are reports combining the c-Met inhibitor with other antitumor agents (PTL 2).

CITATION LIST

PATENT LITERATURE [0007]

PTL1: WO2009/125597

PTL 2: W02013/100014

PTL 3: WO2016/175305

NON PATENT LITERATURE [0008]

NPL 1: PLoS ONE, 11(10): e0164830 (2016)

NPL 2: Molecular Cancer Therapeutics, 12 (12): 2685-2696 (2013)

NPL 3: Cancer Cell, 25: 846-859 (2014)

NPL 4: Frontiers in Immunology, 5: Article 489 (2014)

NPL 5: Cancers, 8(10), 97: 8100097 (2016)

NPL 6: Cancers, 8(11), 103: 8110103 (2016)

NPL 7: Nat. Rev. Cancer, 12 (4): 252-264 (2012)

NPL 8: The New England Journal of Medicine, 366; 26: 2443-2454 (2012)

NPL 9: Cell, 168(4): 707-723 (2017)

NPL 10: Science Translational Medicine, 9 (389): eaal 3604 (2017)

SUMMARY OF INVENTION

TECHNICAL PROBLEM [0009]

Concerning NPL 8 to NPL 10, combined use of an anticancer agent and an antimacrophage agent is expected to produce an enhanced effect.

Concerning PTL 2, combined use of the acyl thiourea compound or salts thereof with an immune checkpoint molecule regulator is not known.

It is accordingly an object of the present invention to provide a novel antitumor agent and a novel antitumor effect potentiator that show marked antitumor effects with reduced side effects.

SOLUTION TO PROBLEM [0010]

The present inventor studied the antitumor effects produced by a combination of an acyl thiourea compound represented by general formula (I) or a salt thereof and an immune checkpoint molecule regulator, and found that these medicinal agents produce prominently higher antitumor effects with no serious side effects when used in combination than when used alone by themselves. It was also found that the acyl thiourea compound or salts thereof greatly reduce the tumor-associated macrophages, which play a major role in the suppression of anti-tumor immune response.

The present inventor also found that an acyl thiourea compound represented by general formula (I) or salts thereof have an immunostimulatory effect.

[0011]

Specifically, the present invention provides the following inventions [1] to [21], [0012] [1] An antitumor agent characterized by coadministration of an acyl thiourea compound represented by the following general formula (I) or a salt thereof, and an immune checkpoint molecule regulator.

[0013] [Chem. 1]

[0014] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C₆-i₄aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [2] The antitumor agent according to [1], wherein the acyl thiourea compound is a compound represented by the general formula (I), in which X represents CH, Y represents O,

R¹ represents a hydrogen atom or a C1-6 alkyl group, R² represents a hydrogen atom, a Cmo alkyl group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent, R³ represents a Ci-₆ alkyl group that may have a substituent, R⁴ represents a halogen atom, and R⁵ and R⁶ each independently represent a hydrogen atom or a halogen atom.

[3] The antitumor agent according to [1] or [2], wherein the acyl thiourea compound is a compound represented by the general formula (I), in which X represents CH, Y represents O, R¹ represents a hydrogen atom or a methyl group, R² represents a hydrogen atom, a Cmo alkyl group that may have a substituent, or a 5- to 7-membered heterocyclic group that may have a substituent and having one to two nitrogen or oxygen atoms, R³ represents a methyl or propyl group that may have a 5- to 7-membered heterocyclic group having one to two nitrogen or oxygen atoms, R⁴ represents a fluorine atom, R⁵ represents a hydrogen atom, and R⁶ represents a halogen atom.

More specifically, the antitumor agent according to [1] is an antitumor agent in which the acyl thiourea compound is a compound selected from the following group of compounds:

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(3-isopropoxypropyl)-7methoxyquinoline-6-carboxamide

N-((2,2-Dimethyl-1,3 -dioxolan-4-yl)methyl)-4-(2-fluoro-4-(3 -(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide

N-(2,3-Dihydroxypropyl)-4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(pyridin-3ylmethyl)quinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(3-(2oxopyrrolidin-1 -yl)propyl)quinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-Nmethylquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N(methoxyethyl)quinoline-6-carboxamide

N-(2-(Diethylamino)ethyl)-4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2morpholinoethyl)quinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(2-(2hydroxyethoxy)ethyl)-7-methoxyquinoline-6-carboxamide

N-(2-Acetamidoethyl)-4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7methoxyquinoline-6-carboxamide

N-( 1,3 -Dihydroxypropan-2-yl)-4-(2-fluoro-4-(3 -(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide tert-Butyl-4-(4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7methoxyquinoline-6-carboxamide)-6-carboxamide)piperidine-l-carboxylate

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(piperidin-4yl)quinoline-6-carboxamide

N-( 1 -(Ethylcarbamoyl)piperidin-4-yl)-4-(2-fluoro-4-(3 -(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2-oxoazepan -3-yl)quinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2-oxo-2(pyrrolidin-1 -yl)ethyl)quinoline-6-carboxamide

N-(l-Acetylpiperidin-4-yl)-4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-(4-fluorophenyl)acetyl)thioureido)phenoxy)-7-methoxy-N-(2oxoazepan-3-yl)quinoline-6-carboxamide (S)-4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(2-(3fluoropyrrolidin-l-yl)-2-oxoethyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2morpholino-2-oxoethyl)quinoline-6-carboxamide

N-(2-(Dimethylamino)-2-oxoethyl)-4-(2-fluoro-4-(3-(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-(4-fluorophenyl)acetyl)thioureido)phenoxy)-N-(2hydroxybutyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(2-hydroxy-2methylpropyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-((l7 hydroxycyclohexyl)methyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-((4-hydroxytetrahydro2H-pyran-4-yl)methyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2(methylsulfonyl)ethyl)quinoline-6-carboxamide [4] The antitumor agent according to any one of [1] to [3], wherein the immune checkpoint molecule regulator is at least one selected from a PD-1 pathway antagonist, an ICOS pathway agonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist.

[5] The antitumor agent according to any one of [1] to [4], wherein the immune checkpoint molecule regulator is at least one selected from a PD-1 pathway antagonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist.

[6] The antitumor agent according to any one of [1] to [5], wherein the immune checkpoint molecule regulator is at least one of a PD-1 pathway antagonist and a CTLA-4 pathway antagonist.

[7] The antitumor agent according to any one of [1] to [6], wherein the immune checkpoint molecule regulator is a PD-1 pathway antagonist.

[8] The antitumor agent according to any one of [4] to [7], wherein the PD-1 pathway antagonist is at least one selected from an anti-PD-1 antibody, an anti-PD-Ll antibody, and an anti-PD-L2 antibody.

[9] The antitumor agent according to [8], wherein the anti-PD-1 antibody is at least one of nivolumab and pembrolizumab, and the anti-PD-Ll antibody is at least one selected from atezolizumab, durvalumab, and avelumab.

[10] The antitumor agent according to any one of [4] to [6], wherein the CTLA-4 pathway antagonist is an anti-CTLA-4 antibody.

[11] The antitumor agent according to [10], wherein the anti-CTLA-4 antibody is at least one of ipilimumab and tremelimumab.

[12] The antitumor agent according to any one of [1] to [3], wherein the acyl thiourea compound represented by the general formula (I) or a salt thereof is 4-(2-fluoro-4-(3(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-methylquinoline-6-carboxamide or a salt thereof.

[13] The antitumor agent according to any one of [1] to [12], wherein a target cancer is at least one selected from melanoma, kidney cancer, lung cancer, head and neck cancer, Hodgkin's lymphoma, bladder cancer, colon cancer, liver cancer, stomach cancer, osteosarcoma and soft tissue sarcoma, breast cancer, and prostate cancer.

[14] An antitumor effect potentiator for immune checkpoint molecule regulators comprising: an acyl thiourea compound represented by the following general formula (I) or a salt thereof as an active component.

[0015] [Chem. 2]

[0016] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci -io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ce-i4 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a Ci-6 alkoxy group, a Ci-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [15] An antitumor agent for treating a cancer patient to whom an immune checkpoint molecule regulator is administered, comprising:

an acyl thiourea compound or a salt thereof, wherein the acyl thiourea compound is a compound represented by the following general formula (I).

[0017] [Chem. 3]

[0018] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ce-i4 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a Ci-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [16] An antitumor agent for treating a cancer patient to whom an acyl thiourea compound or a salt thereof is administered, comprising:

an immune checkpoint molecule regulator, wherein the acyl thiourea compound is a compound represented by the following general formula (I).

[0019] [Chem. 4]

(In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C6-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a Ci-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [17] An antitumor agent, comprising:

an acyl thiourea compound or a salt thereof in combination with an immune checkpoint molecule regulator, wherein the acyl thiourea compound is a compound represented by the following general formula (I).

[0021] [Chem. 5]

[0022] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ce-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² maybe bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a Ci-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [0023] [18] An immunostimulant, comprising:

an acyl thiourea compound of the following general formula (I) or a salt thereof as an active component.

[0024] [Chem. 6]

[0025] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ce-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci 6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [19] A pharmaceutical composition for potentiating effects of a medicament that acts on immunity to prevent or treat disease, the pharmaceutical composition comprising:

an acyl thiourea compound represented by the following general formula (I) or a salt thereof.

[0026] [Chem. 7]

[0027] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ci-,-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci_ 6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [20] A pharmaceutical composition, comprising:

an acyl thiourea compound or a salt thereof with a medicament that acts on immunity to prevent or treat disease in combination, wherein the acyl thiourea compound is a compound represented by the following general formula (I).

[0028] [Chem. 8]

[0029] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [21] An immunostimulant for treating a patient to whom a medicament that acts on immunity to prevent or treat disease is administered, comprising:

[0030] [Chem. 9]

[0031] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [0032]

The present invention also relates to the following embodiments.

(1) A pharmaceutical composition for prevention and/or treatment of a tumor, comprising an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof, and an immune checkpoint molecule regulator.

(2) An antitumor agent for use in prevention and/or treatment of a tumor by coadministration of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof, and an immune checkpoint molecule regulator.

(3) An antitumor agent for use in prevention and/or treatment or a tumor, comprising an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof in combination with an immune checkpoint molecule regulator.

(4) An antitumor agent for use in treatment of a cancer patient to whom an immune checkpoint molecule regulator is administered, the antitumor agent comprising an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof.

(5) Use of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof and an immune checkpoint molecule regulator for manufacture of an antitumor agent.

(6) Use of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof for manufacture of an antitumor agent to be used for a cancer patient to whom an immune checkpoint molecule regulator is administered.

(7) An acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof for potentiating antitumor effects of an immune checkpoint molecule regulator.

(8) Use of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof for potentiating antitumor effects of an immune checkpoint molecule regulator.

(9) Use of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof for manufacture of an antitumor effect potentiator for an immune checkpoint molecule regulator.

(10) A method for preventing and/or treating a tumor, comprising the step of administering a therapeutically and/or prophylactically effective amount of a combination of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof and an immune checkpoint molecule regulator to a patient.

(11) A method for preventing and/or treating a tumor, comprising the step of administering a therapeutically and/or prophylactically effective amount of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof to a cancer patient to whom an immune checkpoint molecule regulator is administered.

(12) A method for preventing and/or treating a tumor, comprising the step of administering a therapeutically and/or prophylactically effective amount of an immune checkpoint molecule regulator to a cancer patient to whom an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof is administered.

(13) An immune checkpoint molecule regulator for use in treatment and/or prevention of a tumor in a cancer patient to whom an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof is administered.

(14) Use of an immune checkpoint molecule regulator for manufacture of an antitumor agent to be used for treatment and/or prevention of a tumor in a cancer patient to whom an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof is administered.

(15) A method for potentiating antitumor effects, comprising the step of administering a therapeutically and/or prophylactically effective amount of an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof to a cancer patient to whom an immune checkpoint molecule regulator is administered.

(16) A product comprising an acyl thiourea compound represented by the foregoing general formula (I) or a salt thereof and an immune checkpoint molecule regulator as a combined preparation (hereinafter, referred to also as kit preparation) to be used simultaneously, successively or with intervals for prevention and/or treatment of a tumor.

ADVANTAGEOUS EFFECTS OF INVENTION [0033]

An antitumor agent of the present invention enables a cancer treatment that is highly antitumor effect (particularly, tumor reduction effect, and delaying of tumor growth (life-prolonging effect)) while reducing side effects, increasing the chances of long-term survival of cancer patients. An immunostimulant of the present invention provides a novel treatment for various diseases (for example, various infections, immunodeficiency diseases, and tumors) that are ameliorable by immunostimulation.

BRIEF DESCRIPTION OF DRAWINGS [0034]

FIG. 1 represents graphs showing the effects of combinations of compound 1 and anti-mouse PD-1 antibody in a mouse model transplanted with mouse colon cancer cell line MC38.

FIG. 2 represents a graph showing the combined effect of three agents, compound 1, anti-mouse PD-1 antibody and anti-mouse CTLA-4 antibody in a mouse model transplanted with mouse breast cancer cell line EMT6.

DESCRIPTION OF EMBODIMENTS [0035]

The present invention relates to an antitumor agent, an antitumor effect potentiator, and a kit preparation characterized by coadministration of an acyl thiourea compound represented by general formula (I) or a salt thereof, and an immune checkpoint molecule regulator (particularly, anti-PD-1 antibody), and to use of these agents, a method for treating tumors, a method for preventing tumors, and a method for potentiating antitumor effects. The present invention also relates to an immunostimulant. As used herein, the language to be coadministered is synonymous with to be used so as to be coadministered.

[0036]

Acyl Thiourea Compound

In the present invention, acyl thiourea compounds or salts thereof are compounds represent by the following general formula (I) or salts thereof.

[0037] [Chem. 10]

[0038] (In general formula (I),

X represents CH or N;

Y represents O or NH;

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci_ 6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring.) [0039]

As used herein, the language may have a substituent used in conjunction with a given structure means that the structure may have one, two, or more substituents at its chemically acceptable positions. As used herein, the language having a substituent used in conjunction with a given structure means that the structure has one, two, or more substituents at its chemically acceptable positions.

The type, number, and position of a substituent on the structure are not particularly limited, and may be the same or different when two or more substituents exist. Examples of the substituent include a halogen atom, a hydroxyl group, a cyano group, a nitro group, an alkyl group of 1 to 6 carbon atoms, a cycloalkyl group of 3 to 7 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, an alkoxy group of 1 to 6 carbon atoms, a carbonyl group, an aminocarbonyl group, a sulfonyl group, an alkylsulfonyl group, an amino group, a mono or dialkylamino group, a carbonylamino group, an acyl group, an oxo group, a saturated or unsaturated heterocyclic group, and an aromatic hydrocarbon group of 6 to 14 carbon atoms.

When these substituents are present, the number of substituents is typically one to three.

The numbers shown in lower case following the symbol C represent the number of carbon atoms. For example, Ci-₆ means one to six carbon atoms.

[0040]

In general formula (I), X is CH or N, preferably CH.

In general formula (I), Y is O or NH, preferably O.

[0041]

In general formula (I), Ci-io alkyl group in the Ci-io alkyl group that may have a substituent represented by R¹, R², and R³ represents a linear or branched alkyl group of 1 to 10 carbon atoms, for example, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octynyl group, or an n-decanyl group.

In general formula (I), substituent in the Ci-io alkyl group that may have a substituent represented by R¹, R², and R³ maybe, for example, any of the substituents exemplified above.

[0042]

In general formula (I), C3-10 cyclic alkyl group in the C3-10 cyclic alkyl group that may have a substituent represented by R¹, R², and R³ represents a cyclic alkyl group of 3 to 10 carbon atoms, for example, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.

In general formula (I), substituent in the C3-10 alkyl group that may have a substituent represented by R¹, R², and R³ may be, for example, any of the substituents exemplified above.

[0043]

In general formula (I), Ce-u aromatic hydrocarbon group in the Ce-u aromatic hydrocarbon group that may have a substituent represented by R¹, R², and R³ represents a monocyclic or bicyclic aromatic hydrocarbon group of 6 to 14 carbon atoms, for example, such as a phenyl group or a naphthyl group.

In general formula (I), substituent in the C₆-i4 aromatic hydrocarbon group that may have a substituent represented by R¹, R², and R³ may be, for example, any of the substituents exemplified above.

[0044]

In general formula (I), saturated or unsaturated heterocyclic group in the saturated or unsaturated heterocyclic group that may have a substituent represented by R¹, R², and R³ represents a monocyclic or bicyclic saturated or unsaturated heterocyclic group having one or two oxygen atoms, one or two nitrogen atoms, or one or two sulfur atoms, for example, such as a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a hexamethyleneimino group, a morpholino group, a thiomorpholino group, a homopiperidinyl group, an imidazolyl group, a thienyl group, a furyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a pyrazolinyl group, a triazolyl group, a tetrazolyl group, a pyridyl group, a pyrazil group, a pyrimidinyl group, a pyridazyl group, an indolyl group, an isoindolyl group, an indazolyl group, a methylenedioxyphenyl group, an ethylenedioxyphenyl group, a benzofuranyl group, a dihydrobenzofuranyl group, a benzoimidazolyl group, a benzooxazole group, a benzothiazolyl group, a purinyl group, a quinolyl group, an isoquinolyl group, a quinazolinyl group, or a quinoxalyl group. Preferably, saturated or unsaturated heterocyclic group in the saturated or unsaturated heterocyclic group that may have a substituent represented by R¹, R², and R³is a 5- to 7-membered saturated heterocyclic ring having one or two nitrogen atoms or one or two oxygen atoms, more preferably a 5- to 7-membered saturated heterocyclic ring having one or two nitrogen atoms, for example, such as a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, or a hexamethyleneimino group.

In general formula (I), substituent in the saturated or unsaturated heterocyclic group that may have a substituent represented by R¹, R², and R³ may be, for example, any of the substituents exemplified above, and is preferably a Ci-₆ alkylcarbonyl group, a Ci-₆alkylaminocarbonyl group, a Ci-6 alkoxycarbonyl group, or an oxo group, more preferably a tert-butoxycarbonyl group, an ethylaminocarbonyl group, an acetyl group, or an oxo group.

[0045]

In general formula (I), nitrogen-containing heterocyclic ring in the nitrogencontaining heterocyclic ring that may have a substituent formed by binding of R¹ and R² with the nitrogen atom may be, for example, a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, or a morpholino group.

In general formula (I), substituent in the nitrogen-containing heterocyclic ring that may have a substituent formed by binding of R¹ and R² with the nitrogen atom may be, for example, any of the substituents exemplified above.

[0046]

In general formula (I), the halogen atom represented by R⁴, R⁵, and R⁶ may be, for example, a fluorine atom, a bromine atom, a chlorine atom, or an iodine atom, and is preferably a fluorine atom.

In general formula (I), the Ci-₆ alkyl group represented by R⁴, R⁵, and R⁶represents a linear or branched alkyl group of 1 to 6 carbon atoms, for example, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a secbutyl group, a tert-butyl group, an n-pentyl group, or an n-hexyl group.

[0047]

In general formula (I), the Ci-₆ alkoxy group represented by R⁴, R⁵, and R⁶represents a linear or branched alkoxy group of 1 to 6 carbon atoms, for example, such as a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an nbutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, or an nhexyloxy group.

[0048]

In general formula (I), the Ci-₆ alkylamino group represented by R⁴, R⁵, and R⁶represents an amino group monosubstituted or disubstituted with the Ci-6 alkyl group above. Examples include a methylamino group, an ethylamino group, a dimethylamino group, a methylethylamino group, an n-propylamino group, an isopropylamino group, an n-butylamino group, a sec-butylamino group, a tert-butylamino group, an n-pentylamino group, and an nhexylamino group.

[0049]

In general formula (I), aromatic hydrocarbon group in the aromatic hydrocarbon group that may have a substituent represented by R⁴, R⁵, and R⁶ represents an aromatic hydrocarbon group of 6 to 14 carbon atoms, as with the case of the Ce-14 aromatic hydrocarbon group. Preferred examples include a phenyl group and a naphthyl group.

In general formula (I), substituent in the aromatic hydrocarbon group that may have a substituent represented by R⁴, R⁵, and R⁶ may be, for example, any of the substituents exemplified above.

[0050]

In general formula (I), saturated or unsaturated heterocyclic ring in the saturated or unsaturated heterocyclic ring that may have a substituent represented by R⁴, R⁵, and R⁶represents a monocyclic or bicyclic saturated or unsaturated heterocyclic group having one or two oxygen atoms, one or two nitrogen atoms, or one or two sulfur atoms, as with the foregoing case. Examples include a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a morpholino group, a thiomorpholino group, a homopiperidinyl group, an imidazolyl group, a thienyl group, a furyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a pyrazolinyl group, a triazolyl group, a tetrazolyl group, a pyridyl group, a pyrazil group, a pyrimidinyl group, a pyridazyl group, an indolyl group, an isoindolyl group, an indazolyl group, a methylenedioxyphenyl group, an ethylenedioxyphenyl group, a benzofuranyl group, a dihydrobenzofuranyl group, a benzoimidazolyl group, a benzooxazole group, a benzothiazolyl group, a purinyl group, a quinolyl group, an isoquinolyl group, a quinazolinyl group, and a quinoxalyl group. Preferably, saturated or unsaturated heterocyclic ring in the saturated or unsaturated heterocyclic ring that may have a substituent represented by R⁴, R⁵, and R⁶ is a 5- to 7membered saturated heterocyclic ring having one or two nitrogen atoms, for example, such as a pyrrolidinyl group, a piperidinyl group, or a piperazinyl group.

In general formula (I), substituent in the saturated or unsaturated heterocyclic ring that may have a substituent represented by R⁴, R⁵, and R⁶ may be, for example, any of the substituents exemplified above.

[0051]

Examples of the ring formed by binding of R⁵ and R⁶ with the phenyl ring include a naphthalene ring, a quinoline ring, a quinazoline ring, an indole ring, a benzimidazole ring, a methylenedioxyphenyl ring, and an ethylenedioxyphenyl ring.

[0052]

The following more specifically describes the substituents in the general formula (I) above.

Examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom.

Examples of the alkyl group of 1 to 6 carbon atoms include a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group.

Examples of the cycloalkyl group of 3 to 7 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

Examples of the alkenyl group of 2 to 6 carbon atoms include a vinyl group and a 2propenyl group.

Examples of the alkoxy group of 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an isopropyloxy group, and an n-butyloxy group.

The saturated or unsaturated heterocyclic group represents a monocyclic or bicyclic saturated or unsaturated heterocyclic group having one or two oxygen atoms, one or two nitrogen atoms, or one or two sulfur atoms, such as above. Examples include a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a morpholino group, a thiomorpholino group, a homopiperidinyl group, an imidazolyl group, a thienyl group, a furyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a pyrazolinyl group, a triazolyl group, a tetrazolyl group, a pyridyl group, a pyrazil group, a pyrimidinyl group, a pyridazyl group, an indolyl group, an isoindolyl group, an indazolyl group, a methylenedioxyphenyl group, an ethylenedioxyphenyl group, a benzofuranyl group, a dihydrobenzofuranyl group, a benzoimidazolyl group, a benzooxazole group, a benzothiazolyl group, a purinyl group, a quinolyl group, an isoquinolyl group, a quinazolinyl group, and a quinoxalyl group.

Examples of the aromatic hydrocarbon group of 6 to 14 carbon atoms include a phenyl group and a naphthyl group.

[0053]

Preferred examples of R¹ include a hydrogen atom and a Ci-io alkyl group. R¹ is more preferably a hydrogen atom or a Ci-6 alkyl group, particularly preferably a hydrogen atom or a methyl group.

[0054]

Preferably, R² is a hydrogen atom, a Ci-io alkyl group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent.

Preferred examples of the substituent on the Ci-io alkyl group include groups selected from a halogen atom, a hydroxyl group, a Ci_₆ alkoxy group, an amino group, a Ci-₆alkylamino group, a di(Ci-6 alkyl)amino group, a hydroxy Ci-e alkoxy group, a Ci-6 alkanoylamino group, an aminocarbonyl group, a Ci-6 alkylaminocarbonyl group, a di(Ci_₆alkyl)aminocarbonyl group, a C3-10 cycloalkyl group, a Ci-₆ alkylsulfonyl group, the heterocyclic group mentioned above, the heterocyclic carbonyl group mentioned above, and an oxo group. Preferably, the heterocyclic ring is a 5- to 7-membered heterocyclic ring having one to two nitrogen atoms or one to two oxygen atoms, for example, such as pyrrolidinyl, piperidinyl, piperazinyl, pyridyl, homopiperidinyl, morpholinyl, dioxolan, and dioxane.

The heterocyclic ring may be substituted with, for example, a halogen atom, a hydroxyl group, an oxo group, a Ci-₆ alkoxy group, a Ci-₆ alkyl group, a Ci_₆ alkanoyl group, a Ci-6 alkylaminocarbonyl group, a Ci-6 alkoxycarbonyl group, an amino group, a Ci-6 alkylamino group, or a di(Ci_6 alkyl)amino group.

[0055]

The saturated or unsaturated heterocyclic group that may have a substituent represented by R² is preferably a 5- to 7-membered heterocyclic group having one to two nitrogen atoms or one to two oxygen atoms, for example, such as a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a pyridyl group, a homopiperidinyl group, a morpholinyl group, a dioxolan group, and an oxane group.

The heterocyclic group may be substituted with, for example, a halogen atom, a hydroxyl group, an oxo group, a Ci-₆ alkoxy group, a Ci_₆ alkyl group, a Ci-₆ alkanoyl group, a Ci-6 alkylaminocarbonyl group, or a Ci-6 alkoxycarbonyl group.

Preferably, R¹ and R², with the nitrogen atom bound thereto, form a nitrogencontaining heterocyclic ring that may have a substituent.

[0056]

Preferably, R³ is a Ci-io alkyl group that may have a substituent, more preferably a Ci-6 alkyl group that may have a substituent, particularly preferably a methyl group that may have a substituent, or a propyl group that may have a substituent. The substituent is preferably a 5- to 7-membered heterocyclic group having one to two nitrogen atoms or one to two oxygen atoms, more preferably a morpholino group.

[0057]

R⁴ is preferably a halogen atom, particularly preferably a fluorine atom. Preferably, R⁴ is substituted at position 2.

[0058]

R⁵ and R⁶ are preferably hydrogen atoms or halogen atoms. Particularly preferably, one of R⁵ and R⁶ is a hydrogen atom, and the other is a halogen atom. Preferably, R⁵ and R⁶ are substituted at positions 3 and 4. When R⁵ is a hydrogen atom and R⁶ is a halogen atom, R⁶ is substituted at preferably position 4.

[0059]

Among the compounds represented by general formula (I), the following compounds are preferred in the present invention.

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(3-isopropoxypropyl)-726 methoxyquinoline-6-carboxamide

N-((2,2-Dimethyl-l,3-dioxolan-4-yl)methyl)-4-(2-fluoro-4-(3-(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide

N-(l,3-Dihydroxypropan-2-yl)-4-(2-fluoro-4-(3-(2phenylacetyl)thioureido)phenoxy)-7-methoxyquinoline-6-carboxamide tert-Butyl-4-(4-(2-fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7methoxyquinoline-6-carboxamide)-6-carboxamide)piperidine-l-carboxylate

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2-oxoazepan -3 -yl)quinoline-6-carboxamide

4-(2-Fhioro-4-(3-(2-(4-fluorophenyl)acetyl)thioureido)phenoxy)-7-methoxy-N-(2oxoazepan-3-yl)quinoline-6-carboxamide (S)-4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(2-(3fluoropyrrolidin-l-yl)-2-oxoethyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-N-(( 1 hydroxycyclohexyl)methyl)-7-methoxyquinoline-6-carboxamide

4-(2-Fluoro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-N-(2(methylsulfonyl)ethyl)quinoline-6-carboxamide.

Among the compounds represented by general formula (I), particularly preferred in the present invention is 4-(2-fhioro-4-(3-(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-Nmethylquinoline-6-carboxamide.

[0060]

The acyl thiourea compound represented by general formula (I) of the present invention includes a solvate such as a stereoisomer, an optical isomer, or a hydrate.

The acyl thiourea compound represented by general formula (I) of the present invention may be a salt, and the salt is preferably a pharmacologically acceptable salt. Examples of such salts include salts of inorganic bases, salts of organic bases, salts with inorganic acid, salts with organic acid, salts with acidic amino acid, and salts with basic amino acid.

[0061]

Specifically, examples of the salts of inorganic bases include alkali metal salts such as sodium salts and potassium salts, and alkali-earth metal salts such as magnesium salts and calcium salts.

Examples of the salts of organic bases include trimethylamine, triethylamine, pyridine, N-methylpyridine, N-methylpyrrolidone, ethanolamine, diethanolamine, triethanolamine, and dicyclohexylamine.

[0062]

Examples of the inorganic acids include hydrochloric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, nitric acid, and phosphoric acid.

Examples of the organic acids include formic acid, acetic acid, propionic acid, malonic acid, succinic acid, glutaric acid, fumaric acid, maleic acid, lactic acid, malic acid, citric acid, tartaric acid, benzenesulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid (methylsulfonic acid).

[0063]

Examples of the acidic amino acids include glutamic acid and aspartic acid. Examples of the basic amino acids include lysine, asparagine, and ornithine.

[0064]

The acyl thiourea compound represented by general formula (I) of the present invention may have a form of a pharmacologically acceptable prodrug. The pharmacologically acceptable prodrug may be any compound, provided that it transforms into an acyl thiourea compound represented by general formula (I) under the physiological conditions of the body, for example, such as by hydrolysis, oxidation, or reduction with gastric acid or enzyme. Examples of such compounds include ester compounds for modifying carboxyl group, such as methyl ester, ethyl ester, propyl ester, phenyl ester, carboxyoxymethyl ester, and ethoxycarbonyl ester. Typical examples of compounds that form such prodrugs include compounds that transform into acyl thiourea compounds represented by general formula (I) under the physiological conditions described in Drug Development, Vol. 7, pp. 163 to 198 (1990), Hirokawa Publishing Company.

[0065]

A specific example of the acyl thiourea compound is 4-(2-fluoro-4-(3-(2phenylacetyl)thioureido)phenoxy)-7-methoxy-N-methylquinoline-6-carboxamide (will be referred to as compound 1) of the following structure.

[0066] [Chem. 11]

Η Η

h₃c.

Ν

Η [0067]

Compound 1 can be synthesized using a known method. For example, synthesis of compound 1 may be based on WG2009/125597 (PTL 1) or WO2016/175305 (PTL3).

The acyl thiourea compound represented by general formula (I) or salts thereof of the present invention directly acts on an immune checkpoint molecule by itself to induce an anti-tumor immune response in the body of a cancer patient and thereby control a tumor escaping from immunity.

[0068]

Immune Checkpoint Molecule Regulator

An immune checkpoint molecule regulator of the present invention directly acts on an immune checkpoint molecule to induce an anti-tumor immune response in the body of a cancer patient and thereby control a tumor escaping from immunity.

The immune checkpoint molecule regulator may be, for example, a substance that facilitates the function of a costimulatory molecule (stimulatory costimulatory molecule), or a substance that suppresses the function of a coinhibitory molecule (suppressive costimulatory molecule).

[0069]

Examples of the immune checkpoint molecule include molecules of the B7 family (e.g., B7-1, B7-2, PD-L1, PD-L2), the CD28 family (e.g., CTLA-4, PD-1), the TNF superfamily (4-1 BBL, OX40L), and the TNF receptor superfamily (4-IBB, 0X40). The immune checkpoint molecule regulator may be a substance that targets such an immune checkpoint molecule. For example, the immune checkpoint molecule regulator may be a PD-1 pathway antagonist, an ICOS pathway agonist, a CTLA-4 pathway antagonist, a CD28 pathway agonist, a BTLA pathway antagonist, or a 4-1BB pathway agonist.

The immune checkpoint molecule regulator of the present invention is preferably at least one selected from a PD-1 pathway antagonist, an ICOS pathway agonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist. From the standpoint of reducing side effects, the immune checkpoint molecule regulator of the present invention is more preferably at least one selected from a PD-1 pathway antagonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist, even more preferably at least one of a PD-1 pathway antagonist and a CTLA-4 pathway antagonist, further preferably a PD-1 pathway antagonist, or a PD-1 pathway antagonist and a CTLA-4 pathway antagonist.

[0070]

The PD-1 pathway antagonist inhibits the immunosuppressive signal from PD-1 expressed on T cells, or from its ligand PD-L1 or PD-L2. Examples of the PD-1 pathway antagonist include an anti-PD-1 antibody, an anti-PD-Ll antibody, an anti-PD-L2 antibody, a PD-1 extracellular domain, a PD-L1 extracellular domain, a PD-L2 extracellular domain, PD1-Ig (a fusion protein of PD-1 extracellular domain and the FC region of Ig), PD-Ll-Ig, PDL2-Ig, PD-1 siRNA, PD-L1 siRNA, and PD-L2 siRNA. The PD-1 pathway antagonist is preferably at least one selected from an anti-PD-1 antibody, an anti-PD-Ll antibody, and an anti-PD-L2 antibody, more preferably at least one of an anti-PD-1 antibody and an anti-PDLl antibody, particularly preferably an anti-PD-1 antibody.

[0071]

The CTLA-4 pathway antagonist inhibits the immunosuppressive signal from CTLA-4 expressed on T cells, or from its ligand B7-l(CD80) or B7-2(CD86). The CTLA-4 pathway antagonist is preferably an anti-CTLA-4 antibody, a CTLA-4 extracellular domain, CTLA-4-Ig, an anti-B7-l (CD80) antibody, or an anti-B7-2 (CD86) antibody, more preferably an anti-CTLA-4 antibody or CTLA-4-Ig, particularly preferably an anti-CTLA-4 antibody.

[0072]

Examples of these antibodies include immunoglobulins (e.g., IgA, IgD, IgE, IgG, IgM, IgY), Fab fragments, F(ab')₂ fragments, single-chain antibody fragments (scFv), singledomain antibodies, and diabodies (Nat. Rev. Immunol., 6:343-357, 2006). The antibodies may be monoclonal antibodies or polyclonal antibodies, including, for example, human antibodies, humanized antibodies, chimeric antibodies, mouse antibodies, llama antibodies, and chicken antibodies.

Preferably, the antibodies are humanized IgG monoclonal antibodies or human IgG monoclonal antibodies.

[0073]

Examples of the anti-PD-1 antibody in the present invention include nivolumab, pembrolizumab, cemiplimab, and spartalizumab. Preferred are nivolumab and pembrolizumab.

Examples of the anti-PD-Ll antibody in the present invention include atezolizumab, durvalumab, and avelumab. Preferred is atezolizumab.

Examples of the anti-CTLA-4 antibody in the present invention include ipilimumab and tremelimumab. Preferred is ipilimumab.

Examples of the CTLA-4-Ig in the present invention include abatacept. Preferred is abatacept.

These antibodies can be produced by using a common known antibody producing method.

The anti-PD-1 antibody is commercially available or scheduled to be available as nivolumab or pembrolizumab. The anti-PD-Ll antibody is commercially available or scheduled to be available as atezolizumab, durvalumab, or avelumab. The anti-CTLA-4 antibody is commercially available or scheduled to be available as ipilimumab or tremelimumab. The CTLA-4-Ig is commercially available or scheduled to be available as abatacept. It is also possible to use these commercially available products.

[0074]

In the present invention, when using two or more immune checkpoint molecule regulators, for example, the anti-PD-1 antibody and the anti-CTLA-4 antibody may be used in combination, or a bispecific antibody capable of binding to both PD-1 and CTLA-4 may be used. Examples of the bispecific antibody include XmAb20717 (PD-1 x CTLA-4).

[0075]

The acyl thiourea compounds represented by general formula (I) or salts thereof have an immunostimulatory effect against humans and other mammals, including, for example, monkeys, mice, rats, rabbits, dogs, cats, cows, horses, pigs, and sheep. As used herein, immunostimulatory effect means the effect to activate immune cells, and induce cell division or production of various cytokines. The acyl thiourea compounds represented by general formula (I) or salts thereof have the effect to stimulate immune cells, particularly T cells. The present invention relates to an immunostimulant containing an acyl thiourea compound represented by general formula (I) or a salt thereof, and to a method for stimulating immunity in a patient in need of prevention or treatment, wherein the method includes administering an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof as an immunostimulant to the patient.

[0076]

With the immunostimulatory effect of acyl thiourea compounds represented by general formula (I) or salts thereof, the acyl thiourea compound represented by general formula (I) or a salt thereof is able to prevent or treat diseases that can be ameliorated by way of immunostimulation, for example, such as various infections, immunodeficiency diseases, diseases caused by weakened immune function due to aging, and virus-related tumors.

[0077]

Examples of infections that can be prevented or treated with the acyl thiourea compound represented by general formula (I) or a salt thereof include parasitic infections (for example, Trypanosoma, malaria parasites, Toxoplasma), bacterial infections (for example, pneumococcus, Mycobacterium tuberculosis, Staphylococcus aureus, Bacillus anthracis, Vibrio cholerae, mycoplasma, Helicobacter pylori), and viral infections (for example, human T-cell leukemia virus (HTLV-1), human immunodeficiency virus (HIV), papillomavirus (HPV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), influenza virus (FLU), hepatitis B virus (HBV), herpes virus, hepatitis C virus (HCV), SARS coronavirus, MERS coronavirus, dengue virus, and Ebola virus).

[0078]

In another aspect, the present invention relates to a pharmaceutical composition containing an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of infection, and an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of infection, and to a method for immunostimulatory prevention or treatment of an infection in a patient in need of prevention or treatment, wherein the method includes administering an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof to the patient.

[0079]

Examples of immunodeficiency diseases that can be prevented or treated with an acyl thiourea compound represented by general formula (I) or a salt thereof include congenital immunodeficiency diseases and acquired immune diseases, particularly, acquired immunodeficiency caused by human immunodeficiency virus (HIV) infection. In this respect, another aspect of the present invention relates to a pharmaceutical composition containing an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory treatment of immunodeficiency disease, and an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory treatment of immunodeficiency disease, and to a method for immunostimulatory prevention or treatment of an immunodeficiency disease in a patient in need of treatment, wherein the method includes administering an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof to the patient.

[0080]

Specific examples of diseases caused by weakened immune function due to aging and that can be prevented or treated with an acyl thiourea compound represented by general formula (I) or salts thereof include pneumonia. In this respect, another aspect of the present invention relates to a pharmaceutical composition containing an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of a disease caused by weakened immune function due to aging, and an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of a disease caused by weakened immune function due to aging, and to a method for immunostimulatory prevention or treatment of a disease caused by weakened immune function due to aging in a patient in need of prevention or treatment, wherein the method includes administering an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof to the patient.

[0081]

Specific examples of virus-related tumors, or tumors caused by viral infection, that can be prevented or treated with an acyl thiourea compound represented by general formula (I) or salts thereof include Burkitt lymphoma, hepatocellular carcinoma, cervical cancer, adult T-cell leukemia, Kaposi's sarcoma, and head and neck cancer. In this respect, another aspect of the present invention relates to a pharmaceutical composition containing an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of virus-related tumor, and an acyl thiourea compound represented by general formula (I) or a salt thereof for the immunostimulatory prevention or treatment of virus-related tumor, and to a method for immunostimulatory prevention or treatment of a virus-related tumor in a patient in need of prevention or treatment, wherein the method includes administering an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof to the patient.

[0082]

Acyl thiourea compounds represented by general formula (I) or salts thereof have an immunostimulatory effect that can potentiate effects of a medicament that acts on immunity to prevent or treat disease. Specific examples of the medicament that acts on immunity to prevent or treat disease include prophylactic vaccines against infections (for example, prophylactic vaccines against infections such as diphtheria, tetanus, and pertussis), anti-virus agents (for example, influenza vaccine, hepatitis B vaccine, interferon a preparations, interferon β preparations, telaprevir, ribavirin, simeprevir, sofosbuvir, ledipasvirsofosbuvir combination preparations, vidarabine, aciclovir, ganciclovir, valganciclovir, nucleoside analog reverse transcriptase inhibitors (NRTI; for example, AZT (zidovudine), ddl (didanosine), ddC (zalcitabine), d4T (stavudine), and 3TC (lamibudine)), non-nucleoside reverse transcriptase inhibitors (NNRTI; for example, nevirapine and delavirdine), protease inhibitors (saquinavir, ritonavir, indinavir, and nelfinavir), and anti-tumor immune response inducers (for example, immune checkpoint molecule regulators, and cancer vaccines (for example, sipuleucel T). In this respect, another aspect of the present invention relates to a pharmaceutical composition containing an acyl thiourea compound represented by general formula (I) or a salt thereof for potentiating effects of a medicament that acts on immunity to prevent or treat disease, and an acyl thiourea compound represented by general formula (I) or a salt thereof for potentiating effects of a medicament that acts on immunity to prevent or treat disease, and to a method for potentiating effects of a medicament that acts on immunity to prevent or treat disease, wherein the method includes administering the medicament and an effective amount of an acyl thiourea compound represented by general formula (I) or a salt thereof to the patient.

[0083]

In the present invention, from the viewpoint of potentiating the antitumor effects of an immune checkpoint molecule regulator or enhancing the immunostimulatory effects with an acyl thiourea compound represented by general formula (I) or a salt thereof, the dose of an acyl thiourea compound represented by general formula (I) or a salt thereof per day of administration is preferably 25 to 100%, more preferably 50 to 100%, even more preferably 60 to 100%, particularly preferably 80 to 100%, most preferably 100% of the recommended dose of when the acyl thiourea compound represented by general formula (I) or a salt thereof is administered alone. The recommended dose in humans is preferably 100 to 1,200 mg/body/day, more preferably 200 to 800 mg/body/day, particularly preferably 200 to 650 mg/body/day.

[0084]

In the present invention, from the viewpoint of potentiating the antitumor effects of an immune checkpoint molecule regulator or enhancing the immunostimulatory effect with the acyl thiourea compounds represented by compound 1 or salts thereof, the dose of the acyl thiourea compounds represented by compound 1 or salts thereof per day of administration is preferably 25 to 100%, more preferably 50 to 100%, even more preferably 60 to 100%, particularly preferably 80 to 100%, most preferably 100% of the recommended dose of when the acyl thiourea compounds represented by compound 1 or salts thereof is administered alone. The recommended dose in humans is preferably 100 to 1,200 mg/body/day, more preferably 200 to 800 mg/body/day, particularly preferably 200 to 650 mg/body/day.

[0085]

In the present invention, from the viewpoint of potentiating the antitumor effects of an immune checkpoint molecule regulator with acyl thiourea compounds represented by general formula (I) or a salt thereof, the dose of the immune checkpoint molecule regulator per day of administration is preferably 30 to 100%, more preferably 50 to 100%, particularly preferably 100% of the recommended dose of when the immune checkpoint molecule regulator is administered alone.

[0086]

In the present invention, from the viewpoint of potentiating the antitumor effects of an immune checkpoint molecule regulator with the acyl thiourea compounds represented by compound 1 or salts thereof, the dose of the immune checkpoint molecule regulator per day of administration is preferably 10 to 50%, more preferably 20 to 40%, particularly preferably 33% of the recommended dose of when the immune checkpoint molecule regulator is administered alone.

[0087]

Specifically, with respect to the recommended dose for administration of nivolumab alone, the approved dose for administration of nivolumab alone is 2 mg/kg (body weight) per administration or 3 mg/kg (body weight) per administration in Japan. Accordingly, in the present invention, the dose of nivolumab per day of administration is preferably 0.3 to 3 mg/kg (body weight) per administration, more preferably 1 to 3 mg/kg (body weight) per administration, even more preferably 2 mg/kg (body weight) per administration or 3 mg/kg (body weight) per administration.

[0088]

With respect to the recommended dose for administration of pembrolizumab alone, the approved dose for administration of pembrolizumab alone is 2 mg/kg (body weight) per administration or 200 mg per administration in Japan. Accordingly, in the present invention, the dose of pembrolizumab per day of administration is preferably 0.2 to 2 mg/kg (body weight) per administration or 20 to 200 mg per administration, more preferably 1 to 2 mg/kg (body weight) per administration or 100 to 200 mg per administration, even more preferably 2 mg/kg (body weight) per administration or 200 mg per administration.

[0089]

With respect to the recommended dose for administration of atezolizumab alone, the approved dose for administration of atezolizumab alone is 1,200 mg per administration in the United States. Accordingly, in the present invention, the dose of atezolizumab per day of administration is preferably 120 to 1,200 mg per administration, more preferably 600 to 1,200 mg per administration, even more preferably 1,200 mg per administration.

[0090]

In the present invention, from the viewpoint of the effect of acyl thiourea compounds represented by general formula (I) or salts thereof potentiating effects of a medicament that acts on immunity to prevent or treat disease, the dose for administration of a medicament that acts on immunity to prevent or treat disease per day is preferably 50 to 100%, more preferably 100% of the recommended dose of when the medicament that acts on immunity to prevent or treat disease is administered alone.

[0091]

With respect to the recommended dose for administration of ipilimumab alone, the approved dose for administration of ipilimumab alone is 3 mg/kg (body weight) per administration in Japan. Accordingly, in the present invention, the dose of ipilimumab per day of administration is preferably 0.3 to 3 mg/kg (body weight) per administration, 1.5 to 3 mg/kg (body weight) per administration, even more preferably 3 mg/kg (body weight) per administration.

[0092]

As used herein, recommended dose is a dose that has been determined through experiments such as in clinical trials to be a quantity that brings about the maximum therapeutic effect while being safe to use without causing serious side effects. Specifically, the recommended dose may be any of the doses approved, recommended, or advised by public institutions or organizations such as the Japan Pharmaceuticals and Medical Devices Agency (PMDA), the US Food and Drug Administration (FDA), and the European Medicines

Agency (EMA), and that are indicated in instructions such as package inserts, interview forms, and treatment guidelines. Preferably, the recommended dose is a dose approved by any of PMDA, FDA, and EMA.

[0093]

When using nivolumab as an immune checkpoint molecule regulator, the dose of a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof may be preferably 0.6 to 10.8 mg, more preferably 0.6 to 10 mg, even more preferably 1.1 to 6.7 mg, particularly preferably 1.1 to 5.4 mg with respect to 1 mg of nivolumab.

[0094]

When using pembrolizumab as an immune checkpoint molecule regulator, the dose of a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof may be preferably 0.5 to 10 mg, more preferably 0.5 to 9.75 mg, even more preferably 1.0 to 6.7 mg, particularly preferably 1.1 to 5.4 mg with respect to 1 mg of pembrolizumab.

[0095]

When using atezolizumab as an immune checkpoint molecule regulator, the dose of a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof may be preferably 0.08 to 1.62 mg, more preferably 0.08 to 1 mg, even more preferably 0.17 to 0.67 mg, particularly preferably 0.17 to 0.54 mg with respect to 1 mg of atezolizumab.

[0096]

When using ipilimumab as an immune checkpoint molecule regulator, the dose of a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof may be preferably 0.6 to 10.8 mg, more preferably 0.6 to 6.7 mg, even more preferably 1.1 to 4.4 mg, particularly preferably 1.1 to 3.6 mg with respect to 1 mg of ipilimumab.

[0097]

The dosing schedule of the antitumor agent of the present invention may be appropriately selected according to factors such as type of cancer, and stage of disease.

In the case of an acyl thiourea compound represented by general formula (I) or salts thereof, the antitumor agent is administered preferably daily, or in a cycle with 5 days of continuous administration followed by a 2-day rest.

When the immune checkpoint molecule regulator is nivolumab, the antitumor agent is administered preferably twice a week, once a week, or once in 2 to 3 weeks. In the case of pembrolizumab, the antitumor agent is administered preferably twice a week, once a week, or once in 3 weeks. In the case of atezolizumab, the antitumor agent is administered preferably twice a week, once a week, or once in 3 weeks. In the case of ipilimumab, the antitumor agent is administered preferably twice a week, once a week, or once in 3 weeks.

[0098]

The number of doses per day of the antitumor agent of the present invention may be appropriately selected according to factors such as type of cancer, and stage of disease.

The antitumor agent is administered preferably once daily, regardless of whether the immune checkpoint molecule regulator is nivolumab, pembrolizumab, atezolizumab, or ipilimumab.

The order of administration of the acyl thiourea compound represented by general formula (I) or a salt thereof of the present invention, and the immune checkpoint molecule regulator may be appropriately selected according to factors such as type of cancer, and stage of disease, and these may be administered in this order or in reversed order, or may be administered simultaneously.

The dosing interval of the acyl thiourea compound represented by general formula (I) or a salt thereof of the present invention, and the immune checkpoint molecule regulator may be appropriately selected according to factors such as type of cancer, and stage of disease. Specifically, these may be administered on the same day or with an interval of at most 2 weeks. Preferably, the compounds are administered on the same day or with an interval of at most 1 week, more preferably on the same day or with an interval of 2 days.

[0099]

The target tumor in the present invention is not particularly limited, as long as enhanced antitumor effects can be produced in the tumor. Preferably, the target tumors are tumors in which acyl thiourea compounds represented by general formula (I) or salts thereof can produce antitumor effects, more preferably malignant tumors involving c-Met, and tumors with high numbers of tumor-infiltrating macrophages.

[0100]

In the case of malignant tumors, specific examples of target cancers in the present invention include head and neck cancer, esophageal cancer, stomach cancer, colon cancer, rectal cancer, liver cancer, gallbladder-bile duct cancer, biliary tract cancer, pancreas cancer, colon cancer, urethral cancer, lung cancer, breast cancer, ovarian cancer, cervical cancer, endometrial cancer, kidney cancer, bladder cancer, prostate cancer, testicular tumor, osteosarcoma and soft tissue sarcoma, leukemia, malignant lymphoma, multiple myeloma, skin cancer, brain tumor, and mesothelioma.

[0101]

The target cancers in the present invention are preferably melanoma, kidney cancer, lung cancer, head and neck cancer, Hodgkin's lymphoma, bladder cancer, colon cancer, liver cancer, stomach cancer, osteosarcoma and soft tissue sarcoma, breast cancer, prostate cancer, esophageal cancer, ovarian cancer, glioblastoma, mesothelioma, multiple myeloma, and urethral cancer, more preferably melanoma, kidney cancer, lung cancer, head and neck cancer, Hodgkin's lymphoma, bladder cancer, colon cancer, liver cancer, stomach cancer, osteosarcoma and soft tissue sarcoma, breast cancer, and prostate cancer, particularly preferably colon cancer, breast cancer, lung cancer, melanoma, osteosarcoma and soft tissue sarcoma, most preferably colon cancer and breast cancer.

[0102]

An acyl thiourea compound represented by general formula (I) or a salt thereof, an immune checkpoint molecule regulator, and a medicament that acts on immunity to prevent or treat disease may be prepared in separate forms containing the respective active components, (kit preparation), or may be prepared in a single form (compounding agent), depending on the dosage forms and the dosing schedules of the active components. In the case of a kit preparation, the agents may be produced and sold as a single package suited for coadministration, or may be produced and sold as separate packages.

[0103]

The dosage form of the antitumor agent of the present invention is not particularly limited, and may be appropriately selected according to the intended treatment. Specific examples of possible dosage forms include oral agents (e.g., tablets, coated tablets, powders, granules, capsule formulations, and liquid formulations), injections, suppositories, patches, and ointments.

In the case of an acyl thiourea compound represented by general formula (I) or a salt thereof, the antitumor agent is preferably an oral agent.

In the case of an immune checkpoint molecule regulator, the antitumor agent may have any of the dosage forms exemplified above. Specifically, in the case of an anti-PD-1 antibody, an anti-PD-Ll antibody, or an anti-CTLA-4 antibody, the preferred dosage form is injection.

[0104]

The antitumor agent, an immunostimulant, and a medicament that acts on immunity to prevent or treat disease of the present invention may be prepared using a pharmaceutically acceptable carrier, using a common known method, depending on the dosage form, regardless of whether these are an acyl thiourea compound represented by general formula (I) or a salt thereof, an immune checkpoint molecule regulator, or a medicament that acts on immunity to prevent or treat disease. The carrier may be any of common carriers used for typical medicinal agents. Examples of such carriers include excipients, binders, disintegrants, lubricants, diluents, solubilizing agents, suspending agents, tonicity agents, pH adjusters, buffers, stabilizers, colorants, flavoring agents, and odor improving agents.

[0105]

The present invention also relates to an antitumor effect potentiator containing an acyl thiourea compound represented by general formula (I) or a salt thereof for potentiation of antitumor effects of an immune checkpoint molecule regulator in a cancer patient. The antitumor effect potentiator is prepared in any of the forms listed above for the antitumor agent.

The present invention also relates to an antitumor effect potentiator containing an immune checkpoint molecule regulator for potentiation of antitumor effects of an acyl thiourea compound represented by general formula (I) or a salt thereof in a cancer patient. The antitumor effect potentiator is prepared in any of the forms listed above for the antitumor agent.

The present invention also relates to an immunostimulant containing an acyl thiourea compound represented by general formula (I) or a salt thereof for potentiation of effects of a medicament that acts on immunity to prevent or treat medical conditions in a patient having a disease ameliorable by immunostimulation. The immunostimulant is prepared in any of the forms listed above for the immunostimulant.

[0106]

The present invention also relates to an antitumor agent containing an acyl thiourea compound represented by general formula (I) or a salt thereof for treatment of a cancer patient to whom an immune checkpoint molecule regulator is administered. The antitumor agent is prepared in any of the forms listed above.

The present invention also relates to an antitumor agent containing an immune checkpoint molecule regulator for treatment of a cancer patient to whom an acyl thiourea compound represented by general formula (I) or a salt thereof is administered. The antitumor agent is prepared in any of the forms listed above.

As used herein, treatment is inclusive of postoperative adjuvant chemotherapy performed to prevent recurrence after surgical removal of tumor, and a preoperative adjuvant chemotherapy performed before surgical removal of tumor.

The present invention also relates to an immunostimulant containing an acyl thiourea compound represented by general formula (I) or a salt thereof for treatment of a patient having a disease ameliorable by immunostimulation, the patient to whom a medicament that acts on immunity to prevent or treat disease is administered. The immunostimulant is prepared in any of the forms listed above.

[0107]

The present invention also relates to an antitumor agent containing an acyl thiourea compound represented by general formula (I) or a salt thereof, wherein the antitumor agent is used with an immune checkpoint molecule regulator for a cancer patient in combination. The antitumor agent is prepared in any of the forms listed above.

The present invention also relates to an antitumor agent containing an immune checkpoint molecule regulator, wherein the antitumor agent is used with an acyl thiourea compound represented by general formula (I) or a salt thereof for a cancer patient in combination. The antitumor agent is prepared in any of the forms listed above.

The present invention also relates to an immunostimulant containing an acyl thiourea compound represented by general formula (I) or a salt thereof, wherein the immunostimulant is used with a medicament that acts on immunity to prevent or treat disease in a patient having a disease ameliorable by immunostimulation in combination. The immunostimulant is prepared in any of the forms listed above.

[0108]

The present invention also relates to a kit preparation containing:

an antitumor agent containing an acyl thiourea compound represented by general formula (I) or a salt thereof; and an instruction manual containing instructions for coadministration of an acyl thiourea compound represented by general formula (I) or a salt thereof, and an immune checkpoint molecule regulator to a cancer patient.

Here, instruction manual may contain instructions indicating the doses specified above, and may or may not be legally binding. Preferably, the instruction manual specifies the foregoing doses as recommended doses. Specific examples of such instruction manuals include package inserts and pamphlets. The kit preparation containing an instruction manual may be such that the instruction manual is printed or attached to the package of the kit preparation, or the instruction manual may be enclosed in the package of the kit preparation, together with the antitumor agent or immunostimulant.

The present invention also relates to a kit preparation containing:

an immunostimulant containing an acyl thiourea compound represented by general formula (I) or a salt thereof; and an instruction manual containing instructions for coadministration of an acyl thiourea compound represented by general formula (I) or a salt thereof, and a medicament that acts on immunity to prevent or treat disease to a patient having a disease ameliorable by immunostimulation.

[0109]

The following describes the present invention in greater detail by way of Examples. It is to be noted, however, that the present invention is in no way limited by the following Examples, and various modifications may be made by a person of ordinary skill in the art without departing from the technical idea of the invention disclosed herein.

EXAMPLE 1 [0110]

An experiment was conducted with mouse MC38 tumor model. Tumor cells were cultured in vitro and transplanted subcutaneously into male mice, six weeks of age, in the right chest region, followed by daily administration of compound 1 and a control antibody. In continuous administration, the preferred minimum dose of compound 1 that produces the maximum efficacy in the mouse was found to be 50 mg/kg when orally administered once daily for 21 days. This dose (oral continuous administration of 50 mg/kg for 21 days, q.d.) is equivalent to the recommended dose of compound 1 in humans when administered alone.

[0111] [Example 1] Combined Effects (Antitumor Effects) of Methanesulfonic Acid Salt of Compound 1 and Anti-Mouse PD-1 Antibody in Colon Cancer Cell Transplant Model

MC38, a mouse colon cancer cell line, was provided by Dr. Yoshihiro Hayakawa (University of Toyama, Toyama, Japan). MC38 was cultured in RPMI 1640 medium containing 10% fetal bovine serum (FBS). MC3 8 was subcultured in a 37°C, 5% CO₂incubator in a 1:3 to 1:5 ratio, one to two times a week.

[0112]

A cell suspension as a suspension of MC38 cells in a 1:1 mixture of phosphate43 buffered saline (PBS) and extracellular matrix component Matrigel was prepared, and the suspension, containing 1 x 10⁶ cells/0.1 mL, was transplanted subcutaneously into a

C57BL/6NCrl mouse (Charles River Laboratories Japan Inc.), six weeks of age, in an area around the right last rib.

After transplantation, a tumor was allowed to grow until it had a tumor volume (TV) of 100 to 200 mm³. The tumor size was measured by measuring the major axis and minor axis of the tumor with a digimatic caliper, and TV was calculated using the following formula.

TV (mm³) = major axis (mm) x minor axis (mm) x minor axis (mm)/2

The animals were divided into groups of 10 using a stratified random grouping method, using TV as an index. The day the grouping was made (N = 10) was designated as Day 1.

[0113]

An electronic balance designed for animals was used for body weight measurement. A percentage of body weight change (BWCn) on day n was calculated from the body weight on day 1 (BW1) and the body weight (BWn) on day n using the following formula.

Percentage of body weight change BWCn (%) = (BWn - BW1)/BW1 x 100 [0114]

A methanesulfonic acid salt of compound 1 was pulverized with an agate mortar, and was prepared into a solution having a concentration of 5 mg/mL as its free form, using a solvent. The compound was then dissolved by sonication to prepare a 50 mg/kg dosing solution. The dosing solution was diluted with solvent to prepare a 25 mg/kg dosing solution, and a 12.5 mg/kg dosing solution. These dosing solutions were orally administered as compound 1, once daily in a dose of 12.5 mg/kg/day, 25 mg/kg/day, or 50 mg/kg/day, continuously for 21 days.

Anti-mouse PD-1 antibody (anti-mPD-1 Ab) was prepared by diluting Anti-Mouse CD279 (PD-1) Functional Grade Purified (Clone: RMP-1-14, Affymetrix) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse PD-1 antibody was intraperitoneally administered in a dose of 0.05 mg/body on the first day (Day 1) of administration and on the 8th day since administration was started.

The medicinal agents shown in Table 1 were administered in the schedules, doses, and dosage forms shown in Table 1 (administered group No. 1 to No. 8). The results are presented in FIG. 1 and Table 1.

[0115]

<£>

+1

OO +1 +ι LT> Ο CM

T— co b* oo

o	b~>	CD	O>	co	OO
	o	O	c5	o	O
+1	+1	+1	+1	+1	+1
co			co	CM
Tt	co	LO	o	CM	o

+1 aS

LO O

O £X

LO

cr

[0116]

A Dunnett's test (significance level 0.05) was conducted to analyze Day 22 TV for each group. The group with sole administration of anti-mouse PD-1 antibody (No. 2), the groups with sole administration of different doses of compound 1 (No. 3 to No. 5), and the groups with coadministration of different doses of compound 1 + anti-mouse PD-1 antibody (No. 6 to No. 8) all had significantly smaller TVs than control group (No. 1), showing antitumor effects. In a Student's t test (significance level 0.05), the compound 1 + antimouse PD-1 antibody coadministered groups had significantly smaller TVs, and showed stronger antitumor effects than the groups with sole administration of compound 1 or the group with sole administration of anti-mouse PD-1 antibody, regardless of the dose of compound 1.

The mean BWC22 of the coadministered groups were not notably different from the groups with sole administration of compound 1 or the group with sole administration of antimouse PD-1 antibody, and the coadministration did not involve increase of toxicity, regardless of the dose of compound 1.

The results showed that coadministration of compound 1 or a salt thereof and the anti-PD-1 antibody produces a significantly higher antitumor effect than when these are administered alone.

[0117] [Example 2] Combined Effects (Effects on Tumor-Associated Macrophage) of Methanesulfonic Acid Salt of Compound 1 and Anti-Mouse PD-1 Antibody in Colon Cancer Cell Transplant Model

MC38, a mouse colon cancer cell line, was provided by Dr. Yoshihiro Hayakawa (University of Toyama, Toyama, Japan). MC3 8 was cultured in RPMI1640 medium containing 10% FBS. MC38 was subcultured in a 37°C, 5% CO2 incubator in a 1:3 to 1:5 ratio, one to two times a week.

[0118]

A cell suspension of MC38 cells containing 2 x 10⁶ cells/0.1 mL, was transplanted subcutaneously into a C57BL/6NJJcl mouse (CLEA Japan, Inc.), six weeks of age, in an area around the right last rib.

After transplantation, a tumor was allowed to grow until it had a TV of 50 to 300 mm³. The tumor size was measured by measuring the major axis and minor axis of the tumor with a digimatic caliper, and TV was calculated using the following formula.

TV (mm³) = major axis (mm) x minor axis (mm) x minor axis (mm)/?

The animals were divided into groups of 5 using a stratified random grouping method, using TV as an index. The day the grouping was made (N = 5) was designated as

Day 1.

[0119]

A methanesulfonic acid salt of compound 1 was pulverized with an agate mortar, and was prepared into a solution having a concentration of 2.5 mg/mL as its free form, using a solvent. The compound was then dissolved by sonication to prepare a 25 mg/kg dosing solution.

The dosing solution was orally administered as compound 1, once daily in a dose of 25 mg/kg/day, continuously for 9 days.

Anti-mouse PD-1 antibody (anti-mPD-1 Ab) was prepared by diluting Anti-Mouse CD279 (PD-1) Functional Grade Purified (Clone: RMP-1-14, Affymetrix) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse PD-1 antibody was intraperitoneally administered in a dose of 0.05 mg/body on the first day (Day 1) of administration.

[0120]

The tumor was collected on the 10th day (Day 10) since administration was started, and a tumor suspension was prepared using a digestive enzyme treatment method. The tumor suspension was then reacted with magnetic beads having immobilized thereon an antibody (anti-mouse CD45 antibody) against CD45 (leukocyte marker) - an antigen commonly expressed on leukocytes, and was passed through a magnetic column to isolate tumor infiltrated leukocytes (TILs). The isolated TILs were reacted with fluorescencelabeled anti-CD45 antibody, anti-CD90.2 (T cell marker) antibody, anti-CDllb (myeloid leukocyte marker) antibody, anti-Ly-6G (granulocytic bone marrow-derived suppressor cell marker) antibody, anti-Ly-6C (monocytic bone marrow-derived suppressor cell marker) antibody, and anti-F4/80 (macrophage marker) antibody, and the fraction of tumor-associated macrophage in TIL was calculated by fluorescence flow cytometry. The definition of tumorassociated macrophage, and the method used to calculate the fraction of tumor-associated macrophage in TIL are as follows.

Tumor-associated macrophage: CD45 positive, CD90.2 negative, CD lib positive, Ly6-G negative, Ly-6C negative, and F4/80 positive

Fraction of tumor-associated macrophage (%) = Number of tumor-associated macrophages 4- Number of CD45 positive cells x 100

The medicinal agents shown in Table 2 were administered in the schedules, doses, and dosage forms shown in Table 2 (administered group No. 1 to No. 4). The results are also 5 presented in Table 2.

[0121] η

[0122]

A Dunnett's test (significance level 0.05) was conducted to analyze the fraction of tumor-associated macrophage for each group. The group with sole administration of compound 1 (No. 3), and the group with coadministration of compound 1 + anti-mouse PD-1 antibody (No. 4) had significantly smaller fractions of tumor-associated macrophage than control group (No. 1), showing a tumor-associated macrophage suppressing effect. The group with sole administration of anti-mouse PD-1 antibody (No. 2) did not show a significant suppressing effect against tumor-associated macrophage.

These results confirmed that compound 1 or salts thereof have immunostimulatory effects, and produce the effects even when compound 1 or salts thereof is used with anti-PD-1 antibody in colon cancer in combination.

[0123] [Example 3] Combined Effects of Three Agents (Antitumor Effects) of Methanesulfonic Acid Salt of Compound 1, Anti-Mouse PD-1 Antibody, and Anti-Mouse CTLA-4 Antibody in Breast Cancer Cell Transplant Model

EMT6, a mouse breast cancer cell line, was obtained from American Type Culture Collection (ATCC). EMT6 was cultured in Waymouth's MB752/1 medium containing 15% FBS. EMT6 was subcultured in a 37°C, 5% CO₂ incubator in a 1:3 to 1:5 ratio, one to two times a week.

[0124]

A cell suspension as a suspension of EMT6 cells in a 1:1 mixture of PBS and extracellular matrix component Matrigel was prepared, and the suspension, containing 1 χ 10⁴cells/0.1 mL, was transplanted subcutaneously into a BALB/c mouse (Charles River Laboratories Japan Inc.), six weeks of age, in an area around the right last rib.

After transplantation, a tumor was allowed to grow until it had a tumor volume (TV) of 50 to 200 mm³. The tumor size was measured by measuring the major axis and minor axis of the tumor with a digimatic caliper, and TV was calculated using the following formula.

TV (mm³) = major axis (mm) x minor axis (mm) x minor axis (mm)/2

The animals were divided into groups of 15 using a stratified random grouping method, using TV as an index. The day the grouping was made (N = 15) was designated as Day 1.

[0125]

An electronic balance designed for animals was used for body weight measurement.

A percentage of body weight change (BWCn) on day n was calculated in the same manner as in Example 1.

[0126]

A methanesulfonic acid salt of compound 1 was pulverized with an agate mortar, and was prepared into a solution having a concentration of 4.2 mg/mL as its free form, using a solvent. The compound was then dissolved by sonication to prepare a 42 mg/kg dosing solution. The dosing solution was orally administered as compound 1, once daily in a dose of 42 mg/kg/day, continuously for 14 days.

Anti-mouse PD-1 antibody (anti-mPD-1 Ab) was prepared by diluting Anti-Mouse CD279 (PD-1) Functional Grade Purified (Clone: RMP-1-14, Affymetrix) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse PD-1 antibody was intraperitoneally administered in a dose of 0.1 mg/body on the first day (Day 1) of administration, and on the 4th day (Day 4), the 8th day (Day 8), and the 11th day (Day 11) since administration was started.

Anti-mouse CTLA-4 antibody (anti-mCTLA-4 Ab) was prepared by diluting In Vivo MAb Anti-Mouse CTLA-4 (CD152) (Clone: 9H10, Bio X Cell) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse CTLA-4 antibody was intraperitoneally administered in a dose of 0.5 mg/body on the first day (Day 1) of administration, and after 4 days (Day 4), 8 days (Day 8), and 11 days (Day 11) from administration.

The medicinal agents shown in Table 3 were administered in the schedules, doses, and dosage forms shown in Table 3 (administered group No. 1 to No. 4). The results are presented in FIG. 2 and Table 3.

[0127]

[0128]

ADunnett's test (significance level 0.05) was conducted to analyze Day 15 TV for each group. The group with coadministration of anti-mouse PD-1 antibody and anti-CTLA4 antibody (No. 3), the group with sole administration of compound 1 (No. 2), and the group with three agents coadministration of compound 1 + anti-mouse PD-1 antibody + anti-mouse CTLA-4 antibody (No. 4) all had significantly smaller TVs than control group (No. 1), showing antitumor effects. In a Student's t test (significance level 0.05), the group with three agents coadministration of the compound 1 + anti-mouse PD-1 antibody + anti-mouse CTLA4 antibody had a significantly smaller TV, and showed stronger antitumor effects than the group with sole administration of compound 1 or the group with coadministration of antimouse PD-1 antibody + anti-mouse CTLA-4 antibody.

The mean BWC15 of the group with three agents coadministration was not notably different from the group with sole administration of compound 1 or the group with coadministration of the anti-mouse PD-1 antibody + anti-mouse CTLA-4. And this showed that the group with three agents coadministration did not involve increase of toxicity.

The results showed that coadministration of compound 1 or salts thereof, anti-PD-1 antibody, and anti-CTLA-4 antibody produces a significantly higher antitumor effect than when these are administered alone.

[0129] [Example 4] Effects (Effects on Tumor-Associated Macrophage) of Methanesulfonic Acid Salt of Compound 1, and Effects of Two Agents of Coadministration of Anti-Mouse PD-1 Antibody and Anti-Mouse CTLA-4 Antibody in Breast Cancer Cell Transplant Model

EMT6, a mouse breast cancer cell line, was obtained from ATCC. EMT6 was cultured in Waymouth's MB752/1 medium containing 15% FBS. EMT6 was subcultured in a 37°C, 5% CO2 incubator in a 1:3 to 1:5 ratio, one to two times a week.

[0130]

A cell suspension as a suspension of EMT6 cells in a 1:1 mixture of PBS and extracellular matrix component Matrigel was prepared, and the suspension, containing 1 x 10⁴cells/0.1 mL, was transplanted subcutaneously into a BALB/c mouse (Charles River Laboratories Japan Inc.), six weeks of age, in an area around the right last rib.

After 4 days from transplantation, the animals were divided into groups of 5 using a stratified random grouping method, using body weight as an index. The day the grouping was made (N = 5) was designated as Day 1.

[0131]

A methanesulfonic acid salt of compound 1 was pulverized with an agate mortar, and was prepared into a solution having a concentration of 4.2 mg/mL as its free form, using a solvent. The compound was then dissolved by sonication to prepare a 42 mg/kg dosing solution. The dosing solution was orally administered as compound 1, once daily in a dose of 42 mg/kg/day, continuously for 6 days.

Anti-mouse PD-1 antibody (anti-mPD-1 Ab) was prepared by diluting Anti-Mouse CD279 (PD-1) Functional Grade Purified (Clone: RMP-1-14, Affymetrix) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse PD-1 antibody was intraperitoneally administered in a dose of 0.1 mg/body on the first day (Day 1) of administration, and on the 4th days (Day 4) since administration was started.

Anti-mouse CTLA-4 antibody (anti-mCTLA-4 Ab) was prepared by diluting In Vivo MAb Anti-Mouse CTLA-4 (CD 152) (Clone: 9H10, Bio X Cell) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse CTLA-4 antibody was intraperitoneally administered in a dose of 0.5 mg/body on the first day (Day 1) of administration, and on the 4th day (Day 4) since administration was started.

[0132]

The tumor was collected on the 7th day (Day 7) since administration was started, and a tumor suspension was prepared using a digestive enzyme treatment method. The tumor suspension was then reacted with magnetic beads having immobilized thereon an antibody (anti-mouse CD45 antibody) against CD45 which is commonly expressed on leukocytes, and was passed through a magnetic column to isolate TILs. The isolated TILs were reacted with fluorescence-labeled anti-CD45 antibody, anti-CD90.2 antibody, antiCD lib antibody, anti-Ly-6G antibody, anti-Ly-6C antibody, and anti-F4/80 antibody, and the fraction of tumor-associated macrophage in TIL was calculated by fluorescence flow cytometry. The definition of tumor-associated macrophage, and the method used to calculate the fraction of tumor-associated macrophage in TIL are as follows.

Fraction of tumor-associated macrophage (%) = Number of tumor-associated macrophages + Number of CD45 positive cells x 100

The medicinal agents shown in Table 4 were administered in the schedules, doses, and dosage forms shown in Table 4 (administered group No. 1 to No.3). The results are also presented in Table 4.

[0133]

[0134]

A Dunnett's test (significance level 0.05) was conducted to analyze the fraction of tumor-associated macrophage for each group. The group with sole administration of compound 1 (No. 2) had a significantly smaller fraction of tumor-associated macrophage than control group (No. 1), showing a tumor-associated macrophage suppressing effect. The group with coadministration of anti-mouse PD-1 antibody and anti-CTLA-4 antibody (No. 3) did not show a significant suppressing effect against tumor-associated macrophage.

These results indicated that compound 1 or salts thereof have immunostimulatory effects in breast cancer.

[0135] [Example 5] Combined Effects (Antitumor Effects) of Methanesulfonic Acid Salt of Compound 1 and Anti-Mouse PD-1 Antibody in Breast Cancer Cell Transplant Model

[0136]

After transplantation, a tumor was allowed to grow until it had a TV of 50 to 200 mm³. The tumor size was measured by measuring the major axis and minor axis of the tumor with a digimatic caliper, and TV was calculated using the following formula.

TV (mm³) = major axis (mm) x minor axis (mm) x minor axis (mm)/2

The animals were divided into groups of 15 using a stratified random grouping method, using TV as an index. The first day of grouping (N = 15) was designated as Day 1.

[0137]

An electronic balance designed for animals was used for body weight measurement. A percentage of body weight change (BWCn) on day n was calculated in the same manner as in Example 1.

[0138]

[0139] [Example 6] Combined Effects (Antitumor Effects) of Methanesulfonic Acid Salt of Compound 1 and Anti-Mouse CTLA-4 Antibody in Breast Cancer Cell Transplant Model

[0140]

A cell suspension as a suspension of EMT6 cells in a 1:1 mixture of PBS and extracellular matrix component Matrigel was prepared, and the suspension, containing IxlO⁴cells/0.1 mL, was transplanted subcutaneously into a BALB/c mouse (Charles River Laboratories Japan Inc.), six weeks of age, in an area around the right last rib.

TV (mm³) = major axis (mm) x minor axis (mm) x minor axis (mm)/2

[0141]

[0142]

A methanesulfonic salt of compound 1 was pulverized with an agate mortar, and was prepared into a solution having a concentration of 4.2 mg/mL as its free form, using a solvent. The compound was then dissolved by sonication to prepare a 42 mg/kg dosing solution. The dosing solution was orally administered as compound 1, once daily in a dose of 42 mg/kg/day, continuously for 14 days.

Anti-mouse CTLA-4 antibody (anti-mCTLA-4 Ab) was prepared by diluting In Vivo MAb Anti-Mouse CTLA-4 (CD152) (Clone: 9H10, Bio X Cell) with PBS in such a manner that the antibody had a predetermined concentration immediately before administration. The anti-mouse CTLA-4 antibody was intraperitoneally administered in a dose of 0.5 mg/body on the first day (Day 1) of administration, and on the 4th day (Day 4), the 8th day (Day 8), and the 11th day (Day 11) since administration was started.

[0143]

While the present invention has been described in detail and with reference to certain embodiments of the invention, it will be apparent to a skilled person that various changes and modifications may be made thereto without departing from the spirit and scope of the invention. This patent application is based on Japanese Patent Application Number 2017-173352 filed September 8, 2017, the entire contents of which are hereby incorporated by reference.

Claims

CLAIMS [Claim 1]

An antitumor agent characterized by coadministration of an acyl thiourea compound represented by the following general formula (I) or a salt thereof, and an immune checkpoint molecule regulator, [Chem. 1]

(in general formula (I):

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C6-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring).
[Claim 2]

The antitumor agent according to claim 1, wherein, in the general formula (I),

X represents CH,

Y represents Ο,

R¹ represents a hydrogen atom or a Ci-₆ alkyl group, R² represents a hydrogen atom, a Ci-io alkyl group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent,

R³ represents a Ci-6 alkyl group that may have a substituent,

R⁴ represents a halogen atom, and

R⁵ and R⁶ each independently represent a hydrogen atom or a halogen atom.
[Claim 3]

The antitumor agent according to claim 1 or 2, wherein, in the general formula (I),

X represents CH,

Y represents O,

R¹ represents a hydrogen atom or a methyl group,

R² represents a hydrogen atom, a Ci-io alkyl group that may have a substituent, or a

5- to 7-membered heterocyclic group that may have a substituent and having one to two nitrogen or oxygen atoms,

R³ represents a methyl or propyl group that may have a 5- to 7-membered heterocyclic group having one to two nitrogen or oxygen atoms,

R⁴ represents a fluorine atom,

R⁵ represents a hydrogen atom, and

R⁶ represents a halogen atom.
[Claim 4]

The antitumor agent according to any one of claims 1 to 3, wherein the immune checkpoint molecule regulator is at least one selected from a PD-1 pathway antagonist, an ICOS pathway agonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist.
[Claim 5]

The antitumor agent according to any one of claims 1 to 4, wherein the immune checkpoint molecule regulator is at least one selected from a

PD-1 pathway antagonist, a CTLA-4 pathway antagonist, and a CD28 pathway agonist.
[Claim 6]

The antitumor agent according to any one of claims 1 to 5, wherein the immune checkpoint molecule regulator is at least one of a PD-1 pathway antagonist and a CTLA-4 pathway antagonist.
[Claim 7]

The antitumor agent according to any one of claims 1 to 6, wherein the immune checkpoint molecule regulator is a PD-1 pathway antagonist.
[Claim 8]

The antitumor agent according to any one of claims 4 to 7, wherein the PD-1 pathway antagonist is at least one selected from an anti-PD-1 antibody, an anti-PD-Ll antibody, and an anti-PD-L2 antibody.
[Claim 9]

The antitumor agent according to claim 8, wherein the anti-PD-1 antibody is at least one of nivolumab and pembrolizumab, and the anti-PD-Ll antibody is at least one selected from atezolizumab, durvalumab, and avelumab.
[Claim 10]

The antitumor agent according to any one of claims 4 to 6, wherein the CTLA-4 pathway antagonist is an anti-CTLA-4 antibody.
[Claim 11]

The antitumor agent according to claim 10, wherein the anti-CTLA-4 antibody is at least one of ipilimumab and tremelimumab.
[Claim 12]

The antitumor agent according to any one of claims 1 to 3, wherein the acyl thiourea compound represented by the general formula (I) or a salt thereof is 4-(2-fluoro-4-(3 -(2-phenylacetyl)thioureido)phenoxy)-7-methoxy-Nmethylquinoline-6-carboxamide or a salt thereof.
[Claim 13]

The antitumor agent according to any one of claims 1 to 12, wherein a target cancer is at least one selected from melanoma, kidney cancer, lung cancer, head and neck cancer, Hodgkin's lymphoma, bladder cancer, colon cancer, liver cancer, stomach cancer, osteosarcoma and soft tissue sarcoma, breast cancer, and prostate cancer.
[Claim 14]

An antitumor effect potentiator for immune checkpoint molecule regulators, comprising:

an acyl thiourea compound represented by the following general formula (I) or a salt thereof as an active component, [Chem. 2]

(in general formula (I):

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C6-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent;

and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a C ιό alkyl group, a Ci-6 alkoxy group, a Ci-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R³ and R⁶ may be bound to each other with the phenyl ring to form a ring).
[Claim 15]

An antitumor agent for treating a cancer patient to whom an immune checkpoint molecule regulator is administered, comprising:

an acyl thiourea compound or a salt thereof, wherein the acyl thiourea compound is a compound represented by the following general formula (I), [Chem. 3]

(in general formula (I):

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C₆-i4 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a υιό alkyl group, a Ci-6 alkoxy group, a Ci-₆ alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring).
[Claim 16]

An antitumor agent for treating a cancer patient to whom an acyl thiourea compound or a salt thereof is administered, comprising:

an immune checkpoint molecule regulator, wherein the acyl thiourea compound is a compound represented by the following general formula (I), [Chem. 4]

(in general formula (I):

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Ci-io alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a C6-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a C1-6 alkoxy group, a C1-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring).
[Claim 17]

An antitumor agent, comprising:

an acyl thiourea compound or a salt thereof in combination with an immune checkpoint molecule regulator, wherein the acyl thiourea compound is a compound represented by the following general formula (I), [Chem. 5]

(in general formula (I):

X represents CH or N;

Y represents O or NH;

R¹, R², and R³ each independently represent a hydrogen atom, a Cuio alkyl group that may have a substituent, a C3-10 cyclic alkyl group that may have a substituent, a Ce-14 aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R¹ and R² may be bound to each other with the nitrogen atom to form a nitrogen-containing heterocyclic ring that may have a substituent; and

R⁴, R⁵, and R⁶ each independently represent a hydrogen atom, a halogen atom, a Ci6 alkyl group, a Ci-6 alkoxy group, a Ci-6 alkylamino group, an aromatic hydrocarbon group that may have a substituent, or a saturated or unsaturated heterocyclic group that may have a substituent, or R⁵ and R⁶ may be bound to each other with the phenyl ring to form a ring).